First Observation of the Hadronic Transition $\mathrm{{\rm Y}}\left(4S\right)\to \eta h_b\left(1P\right)$ and New Measurement of the $h_b\left(1P\right)$ and ${\eta }_b\left(1S\right)$ Parameters

Journal Article · 29 September 2015 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.115.142001 · OSTI ID:1594410

Tamponi, U. ^[1]; Mussa, R.; Abdesselam, A.; Aihara, H.; Arinstein, K.; Asner, D. M.; Atmacan, H.; Aushev, T.; Ayad, R.; Badhrees, I.; Bakich, A. M.; Barberio, E.; Bhardwaj, V.; Bhuyan, B.; Biswal, J.; Bondar, A.; Bonvicini, G.; Bozek, A.; Bračko, M.; Browder, T. E. ; Červenkov, D.; Chen, A.; Cheon, B. G.; Cho, K.; Chobanova, V.; Choi, S. -K.; Choi, Y.; Cinabro, D.; Danilov, M.; Doležal, Z.; Drásal, Z.; Drutskoy, A.; Eidelman, S.; Epifanov, D.; Farhat, H.; Fast, J. E.; Ferber, T.; Fulsom, B. G.; Gaur, V.; Gabyshev, N.; Garmash, A.; Getzkow, D.; Gillard, R.; Goh, Y. M.; Golob, B.; Haba, J.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hedges, M. T.; Hou, W. -S.; Iijima, T.; Inami, K.; Ishikawa, A.; Jaegle, I.; Joffe, D.; Julius, T.; Kato, E.; Katrenko, P.; Kichimi, H.; Kiesling, C.; Kim, D. Y.; Kim, H. J.; Kim, J. H.; Kim, K. T.; Kim, S. H.; Kinoshita, K.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kumita, T.; Kuzmin, A.; Lange, J. S.; Lewis, P.; Libby, J.; Lukin, P.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Moll, A.; Mori, T.; Nakano, E.; Nakao, M.; Nanut, T.; Natkaniec, Z.; Nayak, M.; Nisar, N. K.; Nishida, S.; Ogawa, S.; Okuno, S.; Olsen, S. L.; Ostrowicz, W.; Oswald, C.; Pakhlova, G.; Pal, B.; Park, H.; Pedlar, T. K.; Pesántez, L.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Ribežl, E.; Ritter, M.; Rostomyan, A.; Ryu, S.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Sato, Y.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Semmler, D.; Senyo, K.; Sevior, M. E.; Shapkin, M.; Shebalin, V.; Shen, C. P.; Shibata, T. -A.; Shiu, J. -G.; Shwartz, B.; Sibidanov, A.; Simon, F.; Sohn, Y. -S.; Sokolov, A.; Starič, M.; Steder, M.; Stypula, J.; Tanida, K.; Teramoto, Y.; Trabelsi, K.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Urquijo, P.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vinokurova, A.; Vossen, A.; Wagner, M. N.; Wang, M. -Z.; Wang, X. L.; Watanabe, Y.; Williams, K. M.; Won, E.; Yamaoka, J.; Yashchenko, S.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

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1. Virginia Polytechnic Institute and State University

Using a sample of $771.6\times {10}^6$ $\mathrm{{\rm Y}}\mathrm{{\rm Y}}\left(4S\right)$ decays collected by the Belle experiment at the KEKB $e^{+}{e}^{-}$ collider, we observe, for the first time, the transition $\mathrm{{\rm Y}}\left(4S\right)\to \eta h_b\left(1P\right)$ with the branching fraction $\mathcal{B}\left[\mathrm{{\rm Y}}\right(4S)\to \eta h_b(1P\left)\right]=(2.18\pm 0.11\pm 0.18)\times {10}^{-3}$ and we measure the $h_b\left(1P\right)$ mass $M_{h_b\left(1P\right)}=(9899.3\pm 0.4\pm 1.0)\mathrm{MeV}/c^2$, corresponding to the hyperfine (HF) splitting $\mathrm{\Delta }{M}_{\mathrm{HF}}\left(1P\right)=(0.6\pm 0.4\pm 1.0)\mathrm{MeV}/c^2$. Using the transition $h_b\left(1P\right)\to \gamma {\eta }_b\left(1S\right)$, we measure the ${\eta }_b\left(1S\right)$ mass $M_{{\eta }_b\left(1S\right)}=(9400.7\pm 1.7\pm 1.6)\mathrm{MeV}/c^2$, corresponding to $\mathrm{\Delta }{M}_{\mathrm{HF}}\left(1S\right)=(59.6\pm 1.7\pm 1.6)\mathrm{MeV}/c^2$, the ${\eta }_b\left(1S\right)$ width ${\mathrm{\Gamma }}_{{\eta }_b\left(1S\right)}=(8_{-5}^{+6}\pm 5)\mathrm{MeV}/c^2$ and the branching fraction $\mathcal{B}\left[h_b\right(1P)\to \gamma {\eta }_b(1S\left)\right]=(56\pm 8\pm 4)\%$.

• Research Organization: Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• Contributing Organization: Belle Collaboration
• Grant/Contract Number: SC0009973
• OSTI ID: 1594410
• Report Number(s): PNNL-SA--112064
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 14 Vol. 115; ISSN 0031-9007; ISSN PRLTAO
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English